Pressure actuator

ABSTRACT

A pressure actuator is provided having a stationary plate and a floating plate for holding an element under compression and a base plate separated from said floating plate by a flexible conduit which defines an inner chamber intermediate said floating and base plates. The conduit is comprised of at least one solid member or track, usually two, which defines an enclosure or ring. Depending on the number of tracks one or two elastomeric bands are employed. The edges of the elastomeric band(s) fit into grooves in the tracks to form a continuous conduit, which has a port for pressurizing. With the continuous conduit intermediate the floating and base plates, a significant portion of the surface of the elastomeric sheet or sheets is in contact with the plates. When a work product is introduced between the stationary and floating plates, the conduit is pressurized with a fluid, defining an hermetically sealed chamber which is also pressurized, at a pressure lower than the pressure in the conduit, to provide a uniform work force against the work product. The pressure actuator finds particular use in pressure applications which require high, uniform force to be applied to the work. When the element is to be released, the pressure in the chamber and conduit is released, lowering the element out of engagement with the upper restraining plate.

United States Patent [1 1 Merrill Jan. 21,1975

[ PRESSURE ACTUATOR Robert E. Merrill, San Jose, Calif.

[73] Assignee: Daniel A. Bernstein, Antioch, Calif.

[22] Filed: June 28, 1973 [21] Appl. No.: 374,453

Related U.S. Application Data [63] Continuation-impart of Ser. No. 199,569, Nov. 17,

l97l, Pat. No, 3,742,537.

[75] Inventor:

[52] U.S. Cl 100/269 A, 92/92, 144/281 A, 425/405 [51] Int. Cl B30b 1/32 [58] Field of Search 100/269 A; 92/92; 425/405, 425/DIG. 19; 269/22; 264/DlG, 50; 144/281 Primary Examiner-Billy J. Wilhite Attorney, Agent, or FirmTownsend and Townsend [57] ABSTRACT A pressure actuator is provided having a stationary plate and a floating plate for holding an element under compression and a base plate separated from said floating plate by a flexible conduit which defines an inner chamber intermediate said floating and base plates. The conduit is comprised of at least one solid member or track, usually two, which defines an enclosure or ring. Depending on the number of tracks one or two elastomeric bands are employedv The edges of the elastomeric band(s) fit into grooves in the tracks to form a continuous conduit, which has a port for pressurizing.

With the continuous conduit intermediate the floating and base plates, a significant portion of the surface of the elastomeric sheet or sheets is in contact with the plates. When a work product is introduced between the stationary and floating plates, the conduit is pressurized with a fluid, defining an hermetically sealed chamber which is also pressurized, at a pressure lower than the pressure in the conduit, to provide a uniform work force against the work product.

The pressure actuator finds particular use in pressure applications which require high, uniform force to be applied to the work. When the element is to be released, the pressure in the chamber and conduit is released, lowering the element out of engagement with the upper restraining plate.

6 Claims, 6 Drawing Figures PRESSURE ACTUATOR CROSS REFERENCE TO RELATED APPLICATION BACKGROUND OF THE INVENTION 1. Field of the Invention The subject pressure actuator provides a convenient method for imparting a high, uniform work force to an object. This is particularly useful in the forming of products, adhesive bonding, and the like. Presses are of interest which can be easily fabricated for specific uses. It is therefore desirable to have a pressure actuator which can be readily modified or fabricated to suit either production or specialty requirements.

In developing a pressure actuator, a major consideration is the fabrication of a rubber conduit which cooperates with two platens in defining an inner chamber. The pressure in the inner chamber provides the major work force and the previously available conduits which were heavy elastomeric oval or circular tubes, with or without a flat base, required substantial expertise in their fabrication. Because of the limited size of molding ovens, the size of the sealing conduits were limited. Also, inherent in commercially available molding techniques is a limitation on the pressure which could be maintained in the conduit.

When large platens are required, a plurality of sealing conduits would have to be employed. Complicated plumbing would be involved since means for pressurizing each sealing conduit and inner chamber in a coordinated manner would be required.

Also, there was no convenient means to rigidly fasten the conduits in position. Movement could occur which could result in an uneven application of pressure to the work piece.

It was therefore desirable to have a pressurizable conduit which could be readily fabricated in widely different sizes, and even different regular shapes, e.g. oval, circular, rectangular and the like.

2. Description of the Prior Art U.S. Patents of interest are U.S. Pat. Nos. 877,139; 2,363,779; 2,598,l0; 2,717,421; 2,852,807; 3,l35,998; 3,2l3,739; and 3,237,252.

SUMMARY OF THE INVENTION The subject invention provides a pressure actuator or clamp whereby a relatively large pressure area on the underside of a platen is attainable. A flexible, collapsible, pressurizable conduit is provided which has at least one rigid element, usually two rigid elements defining an enclosure between two platens. Onen or two flexible or elastomeric sheets are employed with the one or two rigid elements, respectively, to define a continuous conduit. A portion of the elastomeric sheet material contacts the plates, so that when the plates are restrained and the conduit pressurized, the conduit defines an hermetically sealed chamber between the plates, which is also pressurized and provides the desired work force.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. I is a perspective view of a pressurized working assembly for a pressure actuator with portions broken away;

FIGv 2 is a cross-sectional elevation along lines 22;

FIG. 3 is cross-sectional elevation of a different portion of the pressure actuator;

FIG. 4 is a cross-sectional elevation of a track;

FIG. 5 is a cross-sectional elevation of an alternate embodiment of a track; and

FIG. 6 is a perspective view partially broken away of an alternate embodiment of the conduit.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS The pressure actuator of the subject invention, and particularly the conduit employed to seal the chamber which provides the working forces, has enhanced flexi bility in design and substantially diminished cost and difficulty in providing the sealing conduit. Because of the difficulties in fabricating high pressure conduits, particularly of any substantial cross-sectional dimensions, the conduits of the subject invention have great advantages in being easily fabricated to any dimension and readily formed in a variety of shapes, such as circles, squares, ovals and rectangles.

In the subject invention, a heavy rubber or elastomeric sheeting is employed, which can be readily fabricated in any length as a band or endless belt and may then be fastened to a rigid member or track of the desired shape. By having the opposite edge of the elastomeric band retained in grooves in the track, an enclosed conduit is formed with the major portion of the rigid member within the conduit. The elastomeric sheet provides a sealing surface which comes in contact with both of the platens of the pressure actuator to provide an hermetically sealed inner chamber when the conduit is pressurized.

The conduit can be formed with either one or two tracks. With one track, the elastomeric sheet extends from a recessed area, or continuous grooves in one surface of the track over and around the track so as to enclose the remaining perimeter of the track and is then inserted into the same or a second recessed area on the same surface. A portion of the track may be exposed or the entire track enclosed within the elastomeric sheet. Where a portion of the track is exposed, the elastomeric sheet surface will be at least at the same level of the exposed surface or extend beyond the exposed surface. In this manner, the elastomeric sheet will be in contact with the platen of the pressure actuator and make an hermetic seal when pressurized.

Where two tracks are employed, conveniently, the tracks are identical in shape and form. Two elastomeric sheets are employed, each of the elastomeric sheets extending from a complimentary groove of one track to the complimentary groove of the other track, so as to provide an inner and outer wall for the conduit. The rigid members provide the roof and floor or top and bottom structure for the conduit.

Once the conduit is assembled, it may then be introduced between the floating plate and a stationary base plate of a pressure actuator, so as to define an inner chamber which can be pressurized between the two plates.

various means can be employed for positioning the conduit in relation to the two plates and inhibit movement during use. Various bolts, fittings, architectural features and the like may be effectively employed to insure the proper positioning of the conduit and its re tention in that position when pressurized. In addition, an outer retaining wall is provided which prevents the undue expansion of the elastomeric material when pressurized. The retaining wall may be an integral part of one of the plates or platens or may be independent of the plates. In addition, it is desirable to limit the extent of separation between the plates, so as to control the volume of the inner chamber, which provides the work force.

For further understanding of the invention, the figures will now be considered. In FIG. I is depicted the portion of the pressure actuator which fits into a housing to provide the work force to the work piece or mold. The pressure plate assembly has an upper floating plate I2 and a lower stationary or base plate 14. Separating the floating plate 12 and stationary plate 14 is the conduit I6 which in FIG. I is depicted rectangular in form, in part, in phantom, As previously indi cated, the conduit can be of any shape to provide a convenient internal chamber size and form.

The conduit 16 has an upper rigid element or track l8 and a lower track 20. The two tracks are conveniently the same, and are positioned as mirror images.

In FIG. 4, a cross section of the rigid member 20 is depicted. The rigid member has an exposed face 22 in which a plurality of threaded chambers 24 are pro vided. Passages 26 in the floating plate 12, as well as complementary passages in the base plate 14, allow access for a bolt 30 to the threaded chambers 24 to fix and hold the conduit 16 in position in relation to the floating plate 12 and the base plate 14.

Because of the symmetry of the assembly, the same number will be assigned to a particular part or structure and will be individually differentiated by letter.

The particular manner in which the conduit 16 is positioned and fastened to the floating plate I2 and stationary plate 14 is depicted in FIG. 2. Socket head screws 30 extend through passages 26 and are threaded into threaded chambers 24. The shoulders of the screw heads 32 engage steps 34, so as to limit the extent to which the head screws 30 enter threaded chambers 24. In this manner, the conduit 16 is held in appropriate position between the two plates l2 and 14. The track 18 which is exemplary of the other track 20, has an inner endless groove 36 and an outer endless groove 40, which symmetrically extend about the periphery of the track 18. The groove wall 42 of the inner groove 36 and the groove wall 44 of the outer groove 40 are of lower height or below the exposed surface 22.

The side walls 46 and 50 extend downwardly and then inwardly, either being curved or beveled. The side walls 46 and 50 provide a relatively mild slope, so as to avoid any sharp corners.

In order to form the conduit, two sheets of elastomeric material are provided which are continuous and are shaped in a form complementary to the rigid mem hers l8 and 20. The sheets form a band or belt. Since the inner sheet 52 and the outer sheet 54 have substantially the same structure differing only in their size, only the outer sheet will be discussed. The sheets are substantially U shaped having flanges pointing inwardly at the edges of the U. The U will be relatively shallow,

that is, the sides of the U are substantially shorter than the base of the U.

The elastomeric sheet 54 has a flange 56 which snugly fits into groove 40. The sheet then extends away from the groove having a flat surface 60 substantially flush with the exposed surface 22 of the rigid member 18. The elastomeric sheet has a side wall 62 joined at a right angle with the connecting wall 64 which con nects with the flange 56. Thus, the elastomeric sheet 54 has a long side wall joining to elastomeric L-shaped members, which serve to lock the elastomeric sheet in the groove in the rigid member and to provide a resil ient surface for hermetic sealing to the plates I2 and 14.

Extending the entire perimeter of the conduit 16 is a restraining wall which extends downwardly from floating plate 12. The restraining wall 70 has inner dimensions so as to freely pass in close proximity to the perimeter of the plate I4. The restraining wall 70 serves to limit the extent of expansion of the outer elastomeric sheet 54. The inner elastomeric sheet 52 does not require rigid restraint, since by pressurizing the conduit in a programmed manner with the inner cham' ber defined by the conduit and the two plates, sufficient restraint is provided by the pressure in the chamber.

Turning now to a consideration of FIG. 2, one or a plurality of arms 72 are rigidly joined to the retaining wall 70 and extend inwardly, so as to serve as a stop. The arms 72 prevent undue separation between the plates 12 and 14 and, therefore, control the maximum volume of the chamber 74 defined by the conduit I6 and the plates 12 and 14. Where the arm 72 runs the length of the retaining wall 70, openings 76 are provided for the socket head screw 30c. The arm 72 may be removably fastened to the wall 70, for reasons which will be explained later.

The inner surfaces defining the inner chamber 74 of the plates 12 and 14 may be flat. However. in order to provide for sufficient room for conduit I6. while maintaining the volume of the chamber 74 desirably small. a stepped surface can be employed as depicted in FIGS, 1 and 2. The plates 12 and I4 have raised platforms or projections 78 and 88 with inner surfaces 86 and respectively, providing for a step whose walls abut the elastomeric sheet side wall 62 and extend the perimeter of the conduit. The step 82 ac, one of the steps not being visible, have a beveled surface 84 b-c. the complimentary inclined faces on the other side of the plates not being visible, where the steps meet the inner faces 86 and 90 of the pltaes 12 and 14 respectively.

The purpose of the inclined faces 84 and the inclined surfaces 92 of the tracks 18 and 20 is to accommodate the inner sheet 52, when the inner sheet bulges in or out. By avoiding sharp, right-angled edges, which would cut into the elastomeric sheet, wear of the elastomeric sheet is minimized. However. as indicated, the projections are primarily provided as a means of controlling the volume of the chamber 74 and are not critical elements of the subject invention. The elastomeric sheet 52 abuts the horizontal side '94 a-d (a and d not being visible). further enhancing the hermetic seal when the conduit 16 is pressurized. The steps 82 also aid in the appropriate positioning of the conduit. further providing for the integral relationship between the various parts and retaining the various parts in their desired spatial juxtaposition.

In FIG. 3, an inflating tube 96 is depicted which extends through channel 100 and into track 20. The inflating tube 96 communicates with chamber 102 which opens into conduit chamber 104. The inflating tube is connected to appropriate valve and pressurizing equipment, so as to provide fluid into the conduit chamber 104 at the desired pressure.

An alternate track 106 is depicted in FIG. 5. In this embodiment, a single groove 110 is provided. The single groove track 106 can be employed with a single elastomeric sheet 112 as depicted in FIG. 6. The flanges 114 and 116 of the elastomeric sheet are inserted in the groove 110, so as to completely encom pass the periphery of the track 106 in the conduit chamber 120. A similar type of arrangement can be employed with the track 18, whereby a portion of the track is exposed, with the remaining periphery of the track within the elastomeric sheet 112.

In carrying out the subject invention, the floating plate 12 is placed with its working surface 122 downward. The conduit 16 is assembled by inserting the flanges 56 and 66 into the grooves 36 and 40, so as to provide a closed chamber 104 encompassing an inner area. The conduit 16 is then fitted into the step 82 a-b and may be bolted into place with socket head screws 30. The lower plate 14 is then seated over the conduit 16 which is fitted into step 82 cd so as to provide a closed chamber 74. A pressurizing inlet tube 124 communicates with chamber 74 and is connected to appropriate valve and pressurizing means analogous to inflating tube 96. Track is then locked in place by means of socket head screws c. Arm 72 is then fastened to retaining wall 70, so as to serve as a stop. Where the arm 72 does not interfere with the assemblying of the plates and conduit, the arm 72 may be permanently fastened to the wall 70.

The presssure plate assembly may now be introduced into a housing having an upper stationary plate. The housing is depicted in U.S. Pat. No. 3,742,537. The work piece is introduced between the floating plate 12 and the stationary plate in the housing which is not depicted. The conduit 104 and the chamber 74 are simultaneously pressurized, with the pressure in the chamber 104 maintained at a higher pressure than the pressure in chamber 74. By having a somewhat equalizing pressure in chamber 74, the inner sheet 52 is prevented from unduly bulging out, and the pressure in chamber 74 acts as an hydraulic retaining wall. The pressure in the chamber 104 serves to press the elastomeric sheet 52 against the walls of the plates 12 and 14 to provide an hermetic seal. As the chamber 104 is pressurized, the conduit will expand so as to raise the floating plate 12 a small distance, locking the work piece in position. The pressure in chamber 74 serves as the working force, applying high pressure uniformly across the work piece.

After completion of the work operation, the pressures in the chambers 74 and 104 are released at a predetermined rate so as to maintain the desired pressure differential between the two chambers. The floating plate is lowered by release of the presusre, and the work piece may be removed from the press. The operation may then be repeated as required.

In accordance with the subject invention, a versatile conduit is provided for use in a pressure actuator. By using a rigid track, various shapes can be machined of widely varying sizes. One or more elastomeric sheets can be formed economically and of various widths. lengths, and thicknesses, as required. Special equipment not generally available is not required to fabricate large conduits. The sheets can be formed with flanges so as to fit snugly in grooves in the track and provided an enclosed chamber in conjunction with two plates. The conduit acts to seal an inner chamber, when the conduit is introduced between two plates. and pressurized with plate movement restrained.

The conduit is readily positioned, and locked into position, because the rigid member can afford threaded openings into which bolts can be introduced. Thus, the conduit can be accurately and symmetrically positioned between the two plates and any movement is in hibited during use of the pressure assembly. Positive seals are assured and higher pressure capability is at tainable with the subject construction.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding. it will be obvious that certain changes and modifications may be practiced within the scope of the appended claims.

What is claimed is:

l. A pressure actuator working assembly comprising first and second platens in confronting relationship;

a pressurizable conduit intermediate said platens having an inner surface defining with said platens a closed inner chamber, wherein said pressurizable conduit comprises a rigid continuous track having groove means in a first surface extending the length of said track for receiving edges of an elastomeric belt;

an elastomeric belt having its opposite edges snugly fitted into said groove means and enclosing the surface of said track opposite said first surface to form a closed chamber with said track and track port means in said track communicating with said closed chamber formed by said track and said belt; a wall extending from one of said platens toward the other of said platens in close juxtaposition to the perimeter of said conduit and said other of said platens;

an inner chamber port in one of said platens communicating with said inner chamber; and

an opening in one of said platens in alignment with said track port means.

2. A pressure actuator assembly in accordance with claim I,

wherein each of said platens has a raised central platform in confronting relationship having a peripheral wall abutting said inner surface of said conduit.

3. A pressure actuator working assembly in accordance with claim I,

having an arm as a stop extending inwardly from said wall and below said other plates.

4. A pressure actuator working assembly comprising first and second platens in confronting relationship;

a pressurizable conduit intermediate said platens having an inner surface defining with said platens a closed inner chamber, wherein said pressurizable conduit comprises first and second rigid continuous tracks of the same structure, each having groove means in a first surface extending the length of said tracks for receiving edges of an elastomeric belt, said first and second tracks having the surfaces opposite said first surface in confronting relationship; first and second endless elastomeric belts having first edges snugly fitted into said groove an opening in one of said platens in alignment with means of said first track and second edges snugly said track port means. l Into Sald groove salld Second track 5. A pressure actuator working assembly in accorformtng a closed chamber with said first and secdance with Claim 4.

nd tracks and port means in said first track communicating with said closed chamber formed by said belts and tracks;

a wall extending from one of said platens toward the other of said platens in close juxtaposition to the perimeter of said conduit and said other of said n dance Chum 4i l having an arm as a stop extending inwardly from said an inner chamber port in one of said platens commu al and below said other plates. nicating with said inner chamber; and

5 wherein each of said platens has a raised Central platform in confronting relationship having a peripheral wall abutting said inner surface of said conduit 6. A pressure actuator working assembly in accor- 

1. A pressure actuator working assembly comprising first and second platens in confronting relationship; a pressurizable conduit intermediate said platens having an inner surface defining with said platens a closed inner chamber, wherein said pressurizable conduit comprises a rigid continuous track having groove means in a first surface extending the length of said track for receiving edges of an elastomeric belt; an elastomeric belt having its opposite edges snugly fitted into said groove means and enclosing the surface of said track opposite said first surface to form a closed chamber with said track and track port means in said track communicating with said closed chamber formed by said track and said belt; a wall extending from one of said platens toward the other of said platens in close juxtaposition to the perimeter of said conduit and said other of said platens; an inner chamber port in one of said platens communicating with said inner chamber; and an opening in one of said platens in alignment with said track port means.
 2. A pressure actuator assembly in accordance with claim 1, wherein each of said platens has a raised central platform in confronting relationship having a peripheral wall abutting said inner surface of said conduit.
 3. A pressure actuator working assembly in accordance with claim 1, having an arm as a stop extending inwardly from said wall and below said other plates.
 4. A pressure actuator working assembly comprising first and second platens in confronting relationship; a pressurizable conduit intermediate said platens having an inner surface defining with said platens a closed inner chamber, wherein said pressurizable conduit comprises first and second rigid continuous tracks of the same structure, each having groove means in a first surface extending the length of said tracks for receiving edges of an elastomeric belt, said first and second tracks having the surfaces opposite said first surface in confronting relationship; first and second endless elastomeric belts having first edges snugly fitted into said groove means of said first track and second edges snugly fitted into said groove means of said second track forming a closed chamber with said first and second tracks and port means in said first track communicating with said closed chamber formed by said belts and tracks; a wall extending from one of said platens toward the other of said platens in close juxtaposition to the perimeter of said conduit and said other of said platens; an inner chamber port in one of said platens communicating with said inner chamber; and an opening in one of said platens in alignment with said track port means.
 5. A pressure actuator working assembly in accordance with claim 4, wherein each of said platens has a raised central platform in confronting relationship having a peripheral wall abutting said inner surface of said conduit.
 6. A pressure actuator working assembly in accordance with claim 4; having an arm as a stop extending inwardly from said wall and below said other plates. 